Make .site container more fluid. Change link style on smaller screens

Just has some issues with viewing [cljs 101](http://swannodette.github.io/2013/11/07/clojurescript-101/) side-by-side with text editor, hope, you consider this reasonable. Right now it does add like 20px padding for width below 568px, so change 569->568 is accompanied by instant position change for content.